For a USB drive I'm looking for a file system (and/or fs creation options) that
- can be mounted without third-party drivers on both a current OS X (>= 10.7.x) and a recent Linux kernel (say stock Ubuntu 12.10)
- with write support
- supports as much Unix semantics and metadata as possible (symlinks, hardlinks, time stamps, Unix permissions, ownership)
Is this feasible? It seems like FAT is the safest bet in terms of compatibility but of course it doesn't do Unix permissions. NTFS seems to be read-only on OS X and doesn't support Unix permissions (and I'd be scared of conflicts in two reverse-engineered interpretations of NTFS). The Linux ext* file systems only work with extra drivers on OS X. HFS+ support in Linux seems to be not quite stable (or is it totally stable after turning off journaling?) Since the Mac is BSD-based I'd guess some variant of UFS should work on both platforms?
Clarification: I do not intend to mount the USB drive simultaneously on two computers (this would be somewhat hard to pull off via the USB interface anyhow, wouldn't it?)